Strainer for pump jacks



Jan. 4, 1949. E. P. GRIME STRA'INER FOR PUMP JACKS 4 Filed April 10,1945 Patented Jan. 4, 1949 UNITED STATES PATENT OFFICE STRAINER FOR PUMPJACKS Edward P. Grime, Los Angeles, Calif. Application April 10, 1945,Serial No. 587.540

3 Claims. 1

My invention relates to strainers for pump jacks, and among the objectsof my invention are:

First, to provide a strainer which is interposed between the reservoirand working cylinder of a pump jack in such a manner that it may bereadily removed for cleaning or replacement.

Second, to provide a strainer equipped pump jack which is simple ofconstruction and compactly arranged.

With the above and other objects in view, reference is directed to theaccompanying drawings, in which:

Fig. 1 is a side elevational view of a pump jack equipped with mystrainer.

Fig. 2 is an enlarged fragmentary sectional view thereof taken through22 of Fig. 1, showing the strainer in position..

Fig. 3 is a transverse sectional view taken through 3-3 of Fig. 2.

Fig. 4 is an enlarged side elevational view of the strainer, removedfrom the pump jack.

A hydraulic jack which is adapted to incorporate my strainer, includes arelatively flat base structure i, which supports a reservoir inner shell2 and a reservoir outer shell 3 defining an annular reservoir 4. Withinthe inner shell 2 is mounted a cylinder liner 5 which contains a piston6.

The base structure is provided with a laterally directed ledge 8 havingan internally threaded socket 9 which receives a pump unit Ill. The pumpunit includes an adapter fitting H intended to screwthread into thesocket 9 and containing an intake port l2 and an outlet port l3controlled by suitable ball check valves. The fitting supports thecylinder H of the pump unit containing a suitable piston (not shown) andfrom which extends a piston rod IS. A suitable handle 16 is provided foroperating the piston rod [5.

Th intake port 12 is connected to a reservoir 4 by a reservoir passage11. The outlet port I3 is connected with the interior of the cylinderliner 5 by a jack cylinder passage l8. The passages H and i8 extendunder the socket 9.

The passage I! is counterbored as indicated by 19 and such counterboreextends radially outwardly to the extremity of the ledge 8. Port l2continues through the bottom of the socket 9 and intersects the sidewall of the counterbore IS. The outer portion of the counterbore isthreaded to adepth beyond the intersection of the port l2 and is adaptedto receive a strainer unit 20.

The strainer unit includes a stem 2| having two threaded portions 22 and23 separated by the stem 2| which is smaller than the threaded portionsand cooperates with such portions to provide an annular chamber 24. Whenthe strainer unit is fitted in the counterbore the threaded portions arelocated at opposite sides of the port 12 with the chamber 24 in registrytherewith. A socket 2'5 intersects the inner end of the stem 2| andcommunicates with the chamber 24 by means of radial ports 26. A tubularstrainer element 21, preferably formed of closely woven wire mesh closedat one end, is fitted by its other or open end over the inner extremityof the stem 2|. The strainer element may be soldered or press fitted orotherwise secured to the stem so that it may be inserted or removed as aunit therewith. The outer end of the stem 2| is provided with a head 28and gasket which sealingly engages the outer end of the counterbore.

Fluid from the reservoir passes through the strainer element 21 into thesocket 25 through ports 26 around the chamber 24 and into the intakeport I2. The inner set of threads 22 need not be fluid tight for inactual practice the normal clearance between the mating portion of thethreads provides a bypass which is more restricted in area than theopenings in the strainer unit.

In the structure shown, the pump unit is a single acting pump, and arelief valve (not shown) is employed for returning fluid from thecylinder 5 to the reservoir 4. Because of the location of the strainer,it is readily accessible.

Many other embodiments of the invention may be resorted to withoutdeparting from the spirit of the invention.

I claim:

1. A removable strainer unit for pump jacks wherein a base structure isprovided with a passageway forming in part a strainer cavity open at itsouter end and intersected intermediate its ends by a lateral port, thewalls of said cavity being screw-threaded from their outer ends inwardlyto a point beyond said lateral port, said strainer unit comprising: astem having spaced screw-threaded portions, said stem being reduced indiameter between said screw-threaded portions and cooperating therewithto form an annular channel; a head at one end of said stem forming ashoulder and adapted to seat against said base structure at the outerend of said strainer cavity, and said screw-threaded portions fittingthe screw threads of said strainer cavity on opposite sides of saidlateral port when the stem is screwed therein; said stem having a socketextending into its end remote from said head and 3 having lateralopenings communicating between said socket and the annular channel; anda strainer element secured to said stem and extending from the socketend thereof.

2. A strainer unit for pump jacks wherein the pump jackhas a strainercavity connecting a coaxial and a lateral passage, the walls of saidcavity being screw-threaded in the region of said lateral passage and asealing face at the outer end of said cavity, said strainer comprising:a stem having a head at one end forming a shoulder adapted to seatagainst said sealing face and a socket at its other end, the stem alsohaving axially inner and outer screw-threaded portions, said stein beingof smaller diameter than said threaded portions in the regiontherebetween and cooperating with said portions to provide an annularchamber on opposite sides of said lateral passage; said annular chamberadapted tovoccupy a position in registry with said lateral passage andsaid stem having ports communicating between said socket and saidannular chamber, said screw-threaded portions fitting the screw threadsof said cavity on opposite sides of said lateral passage; and a strainerelement covering the socket end of said stem and continuing axiallytherefrom.

3. A strainer unit for insertion in a screwthreaded counterborecommunicating between an axially directed passage continuing from itsinner end and a lateral passage intermediate its ends,.the outer end ofsaid counterbore being open, the screw-threaded portion of saidcounterbore being connected intermediate its extremities by said lateralpassage, said strainer unit comprising: a stem sealingly engageable withthe walls surrounding the outer open end of said counterbore, said stemincluding spaced sets of screw threads, said stem being reduced indiameter between said screw threads and cooperating therewith to form anannular chamber adapted to communicatewith saidlateral passage when saidsets of screw threads fit the screw threads oi: said counterbore atopposite sides of said lateral passage, said stem also being bored toform a passage communicating between its inner end and said annularchamber; and a tubular strainer closed .at one end and secured by itsother end to said stem whereby upon insertion of said stem in saidcounterbore a strainer interrupted passageway is formed between saidaxial passage and said lateral passage.

EDWARD P. GRIME.

REFERENCES CITED :The following references are of record in the file.of.this patent:

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